Electronic cigarettes and lung toxicity

ABSTRACT

The use of electronic cigarettes (e-cigarettes) in the United States has steadily increased since their introduction into the market in 2007. These devices deliver nicotine through the vaporization of a liquid which contains a vehicle (propylene glycol or glycerin), artificial flavoring, and nicotine. The combustion of these liquids creates a vapor containing particulates, multiple chemicals, and nicotine. The long-term safety of these products is unknown. Studies in healthy, non-smoking volunteers and smokers with no clinical pulmonary disease have demonstrated that the inhalation of e-cigarette vapor has minimal short-term effects on pulmonary function. The exposure of cell cultures to e-cigarette liquid or aerosols has been shown to reduce cell viability, induce cytokine production, and cause oxidative stress. The exposure of animals (mice and rats) to e-cigarette aerosols induces inflammatory responses in the lungs and delays the clearance of bacterial and viral challenges. There are a small number of case reports of patients developing acute pulmonary toxicity following the use of e-cigarettes. Two patients have developed lipoid pneumonia following the use of e-cigarettes for 3 and 7 months. Finally, several studies suggest that patients with chronic lung disease who switch from tobacco cigarettes to e-cigarettes can have improvement in lung function (asthmatics) and a reduction in the number of exacerbations (chronic obstructive pulmonary disease). Clearly, the public and the medical profession need more information about the long-term complications associated with the use of e-cigarettes and their benefit in smoking cessation efforts.